Important player for us no doubt, on his day there's nothing more enjoyable than watching him stride through the middle, brushing off the opposition and making things happen. His ability to keep the ball and pick out passes that most others wouldn't even see let alone attempt stands him apart from most. He shows up on the big occasions pretty much every time. He scores big goals and puts the fear of god into most players he's up against.
That said there are parts of his game that still infuriate me. He doesn't win anything in the air, ever. He often tries to nick the ball (unsuccessfully) when going in for a tackle instead of using his strength and power. Then there are the not so big games when he plays like its a chore and he's doing us a favour.
I can live with his perceived weaknesses though as the overall package is truly awesome, we're lucky to have him and I hope he's here for the next couple of years.
To answer the OPs question, I'd say no. I think Silva and Aguero will finish up being known as our best ever players - well, until Messi signs in 2 years..